Crabgrass is social networking, group collaboration, and network organizing Web application. It consists of a solid suite of group collaboration tools such as private wikis, task lists, a file repository, and decision making tools. Work is currently being done on a large user interface overhaul, better social networking tools, blogs, and event calendars, as well as better support for collaboration and decision making among independent groups.

Dragora is a trustworthy GNU/Linux-Libre distribution based on the concept of simplicity with the goal of being a multi-purpose operating system. Dragora respects the freedom of the user with the values of Free Software and provides control to those who use it. It is developed entirely by volunteers and it is published under the terms of the GNU General Public License.

Ductus is a wiki system designed to handle arbitrarily-structured content and a variety of workflows. With Ductus, programmers can easily define classes of structured content, providing rich mechanisms for user interaction. For instance, the Wikiotics project uses Ductus to allow people to collaborate on "language lessons," which can later be used as quizzes or flashcards. Such modes of interaction are not possible with most wikis, which are designed primarily to handle freely-structured text.

GNU Anubis is an SMTP message submission daemon. It represents an intermediate layer between the mail user agent (MUA) and mail transport agent (MTA), receiving messages from the MUA, applying to them a set of predefined changes, and finally inserting modified messages into an MTA routing network. The set of changes applied to a message is configurable on a system-wide and per-user basis. The built-in configuration language used for defining sets of changes allows for considerable flexibility and is easily extensible.

GNU Mach is the microkernel upon which a GNU Hurd system is based. It provides an Inter Process Communication (IPC) mechanism which the Hurd uses to define interfaces for implementing in a distributed multi-server fashion the services a traditional operating system kernel provides. Mach is particularly well-suited for SMP and network cluster techniques. Thread support is provided at the kernel level, and the kernel itself takes advantage of that. Network transparency at the IPC level makes resources of the system available across machine boundaries.

GNU Mailutils is a rich and powerful protocol-independent mail framework. It contains a series of useful mail libraries, clients, and servers. These are the primary mail utilities for the GNU system. The central library is capable of handling electronic mail in various mailbox formats and protocols, both local and remote. Specifically, this project contains a POP3 server, an IMAP4 server, and a Sieve mail filter. It also provides a POSIX "mailx" client and a collection of other handy tools.

The GNU Modula-2 compiler is one of a number of front end languages to GCC (the GNU Compiler Collection). As such, it has been designed to coexist with other GCC languages. For example, it can be used in mixed language projects and it can catch C++ exceptions and throw exceptions which can be caught by C++. Users can also exploit conditional compilation and full gcc backend optimization and architecture coverage. GNU Modula-2 can produce position independent code and can easily produce shared libraries from modules. The compiler provides a swig interface file generator option, which allows scripting languages such as Python to import modules written in Modula-2 and also catch exceptions thrown by Modula-2. The compiler translates PIM2, PIM3, PIM4, and ISO dialects of Modula-2.

GNU Radius is a RADIUS server and an accompanying set of monitoring utilities. It features MySQL and PostgreSQL interfaces for authentication and/or logging (the ODBC interface allows you to use almost any existing DBMS for that purpose), the ability to rewrite RADIUS requests from various NASs to normalize them to a more understandable format, and the ability to completely customize the behavior of RADIUS authentication and accounting based on NAS and user attributes.

GNU Recutils is a set of tools and libraries to access human-editable text-based databases called recfiles. A recfile contains data structured as a sequence of records. The rec format supports data integrity with the usage of record descriptors (keys, mandatory fields, field types, etc.) as well as the ability of record fields to refer to other records. Despite its simplicity, recfiles can be used to store medium-sized databases. The GNU recutils suite comprises a texinfo manual describing the Rec format, a C library (librec) providing a rich set of functions to access rec files, a set of C utilities that can be used in shell scripts and in the command line to operate on rec files, and an Emacs mode (rec-mode).

GNU `tar' saves many files together into a single tape or disk archive, and can restore individual files from the archive. It includes multivolume support, the ability to archive sparse files, automatic archive compression/decompression, remote archives and special features that allow `tar' to be used for incremental and full backups. It also includes `rmt', the remote tape server (the `mt' tape drive control program is in GNU `cpio').